The M3 is closer to a 50/50 weight distribution,weighs about 500 lbs less,one is less of a pig and more balanced. In case you didn't know the m3 loses ground in straightaways when racing a GT500.The 3 series is the most copied car in the world also known as the benchmark,I've never heard anyone refer to the Mustang as the benchmark. I like to reward originality with my money.

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The original Mustang was one of the most copied cars ever produced and an entire category of cars (Ponycars) was named after it.